Machine for cutting internal flutes.



V 1). E. ROSS. MACHINE FOR CUTTING INTERNAL I'LUTES.

APPLICATION FILED NOV. 26, 1907.

961,53? Patented June 14,1910.

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D. E. ROSS. MACHINE FOR CUTTING INTERNAL FLUTBS.

APPLIOATION FILED NOV. 26, 1907.

Patented June 14, 1910.

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ANDREW B. GRAHAM 60.. PHuTQ-UTHOGRAPNERS.wAsuiNGToN u c CMMMW.

D. E. ROSS. I MACHINE FOR CUTTING INTERNAL FLUTES.

APPLICATION FILED NOV. 26,1907.

961,53? Patented June.14,1910.

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DAVID E. ROSS, OF BROOKSTON, INDIANA, ASSIGNOR TO ROSS GEAR AND TOOLCOMPANY, OF LA FAYETTE, INDIANA, A CORPORATION OF INDIANA.

MACHINE FOR CUTTING INTERNAL FLUTES.

senses.

Application filed November 26, 1907.

T 0 all whom it may concern:

Be it known that 1, DAVID E. Ross, residing at Brookston, in the countyof White and State of Indiana, have invented a certain new and usefulImprovement in Machines for Cutting Internal Flutes, of which thefollowing is a full, clear, and exact description, reference being hadto the accompanying drawings.

This invention relates to machines for cutting spiral internal flutes;and, while it is adapted for more general application, it is designedmore particularly for cutting the spiral flutes in the housing of mysteering gear mechanism for automobiles and the like that is shown in myapplication No. 316,59t filed May 1 1th, 1906. In the said steeringmechanism, a threaded member is adapted to move longitudinally within anouter housing with which it has threaded engagement, sothat when thesaid member is moved longitudinally it will be given a rotary movementwithin the housing. The steering knuckle of the vehicle is connectedwith the said longitudinally movable member, and as the latter is turnedthe steering wheel of the vehicle is turned. Reference is thus made tothe said steering gear in order that it may be clear that lost motion besecurely provided against, to accomplish which it is necessary that theflutes in the outer housing be square or of uniform width throughouttheir entire depth, thus making it necessary to give the cutter-bits bywhich the flutes are produced, an absolutely parallel movement as theyare fed into the flutes.

My present invention, therefore, consists of a cutter-bar carrying aplurality of cutter-bits, said cutter-bar being given a longitudinal anda rotary motion, and mechanism for feeding outwardly the cutter-bits insuch a manner as to keep them always parallel.

A further object of the invention is to combine with the feedingmechanism for the cutter bits an automatic device for stopping themachine when the flutes have been cut to the proper depth.

Other objects of my invention will be specifically set forth in thefollowing specification which is descriptive of the drawingsaccompanying this application, in which drawings Figure 1 shows a rearelevation of my ma Specification of Letters Patent.

Patented June 14, 1910.

Serial No. 403,895.

chine, the belt shifting lever being shown in section. Fig. 2 is a sideelevation of the machine. Fig. 8 is a transverse section takensubstantially on line 33 of Fig. 1. Fig. 4 is a vertical section takensubstantially on line 4t4 of Fig. 3, and showing the belt shiftingmechanism. Fig. 5 is a horizontal section taken on line 55 of Fig. 1.Fig. 6 is a rear elevation of the cutter-bar and the mechanismimmediately connected there with for operating the bar and for feedingthe cutter-bits. Fig. 7 is a central sectional View through the lowerpart of the shank carrying the cutter-bar, said View being taken on line77 of Fig. 8. Fig. 8 is a bottom plan view of the main shank shown inFigs. 6 and 7 Fig. 9 is an enlarged sectional view taken verticallythrough Fig. 1 on the line 9-9, certain parts being broken away andomitted for purpose of clearness of illustration. Figs. 10 and 11 aredetailed views showing parts of the feeding mechanism for thecutter-bits.

Taking up a detailed description of the invention by reference to thedrawings, in which the same reference characters designate the sameparts throughout the several views, 1 and 2 represent the side housingsof the machine, which are secured together at their upper ends by across plate 3. On their inner faces these housings are provided withvertically extending guide ribs 4, to which ribs there are stationarilysecured transverse cross-heads 5 and 6, said cross-heads beingadjustable vertically along the ribs in order that they may be placed inany desirable location, in which location they may be secured in anysuitable manner, as by set screws 7 Journaled in the housings is atransverse drive-shaft 8, on one end of which is journaled aloose-pulley 9, and keyed to which adjacent said loose-pulley is adrive-pulley 10, said pulleys being driven by a belt 11. Secured to theshaft 8, adjacent to each of the housings 1 and 2, are pinions 11. Thesepinions mesh with gear wheels 12, which are journaled on either side ofthe machine on the studs 13, projecting from the housings. But one setof said pinions and gear wheels appears on the drawings. Each of thesegear wheels is provided with a crankpin 14, and connected with saidcrank-pins and extending upwardly therefrom are connecting-rods 15, saidrods being likewise connected at their upper ends with pins 16 on theends of a movable crosshead 17, said cross-head being guided in itsvertical movement in slots 18 formed in the upper ends of the housings.From this description it will be understood that, as the drive-pulley 10is rotated, the pinions 11 and the gears 12 will be turned, the latterat a comparatively slow speed, and the rotation of the gear wheels willcause the vertical reciprocation ofthe cross-head 17.

Screwed and pinned, or otherwise securely attached to the cross-head 17atits center, is a downwardly extending, cylindrical shank 19, saidshank being, provided at its lower end with a centrally located threadedsocket 20, as shown in Figs. 7, 8 and 9. Into this socket I. screw theupper end of the feed-rod 21, said feed-rod extending downwardly andcentrally through the feed-wheel 22 and the cutter-bar 23, saidcutter-bar extending throughthe center of the stationary cross-head'5,in which it is guided. The feed-screw isprovided at its upper end with aslot or keyway 24, and'the feed-wheel 22 carries a key 25 by means ofwhich it is connected to the feed-screw so as to turn therewith, but becapable of longitudinal movement thereon. By turning the feed-wheel22,.t-herefore, the screw 21 is screwed into or out of the socket 20 inthe shank 19, which operation results in feeding the cutterbits 26inwardly or outwardly with respect to the cutter-head. Near its lowerend the feed-screw 21 is turned down to a smaller diameter. at 27,forming a shoulder at 28. Carried upon the smaller portion, 27 of thefeed-screw, are cones 29, 30 and 31, said cones being held in properposition on the feed-screw by a nut. 32, which is screwed to the lowerend'of the feed-screw. By setting up on this nut, the cones are securelyclamped together and forced against the shoulder 28 on the feed-screw.

The cutter-bits are elongated andare set in recesses 33 inthe-cutter-bar so as to stand vertically in the bar. The cutting edge ofthebit is located on a diamond shaped projection 34 on the bit; and, inthe beginning of the operation, the bits are held within thecutter-barso that these projections are substantially withdrawn into therecesses. The cones 29, 30 and 31.are so formed as to leave angularcircumferential recesses between theirconical faces, and, into theserecesses, angular arms 35 on the rear of the cutterbits project, saidarms substantially fitting across said recesses so as to prevent anylost motion between the bits and cones. Further-- more, the cutter-bitsare of such length and size as to fit securely within the recesses 33 sothere can be no lost motion between the cutter-bits and the cutter-bar23.. The angular arms 35 are parallel witheach other, and, being locatednear the respective ends of the cutter-bits, the latter will be moved inand out, maintaining their parallelism with the axis of the cutter-bar.

It will'be understood from this description that, it being impossible tomove the cutter-bits longitudinally with respect to the cutter-bar,vertical reciprocation-of the feedscrew 21 and the cones thereonwithrespect to the cutter-bar, will result in. camming outwardly andinwardly the cutter-bits in the recesses33 of the cutter-bar. It willalso be-understood that the distance which the projections 34 extendbeyond. the surface of the cutter-bar willdepend upon the movementprovided for between the cones V and the cutter-bar.

As the cutter-bar is reciprocat'ed, it is given a rotary motion in orderthat the projections 34 of the cutter-bits may. cut spiral flutes in thehousing upon which they operate. This rotary motion is imparted to thecutter-bar by a spring-pressed block 36,

which is mounted in the stationary crosshead 5 and has an inwardlyprojecting tongue 37 that extends into a deep spiral flute 38 on thecutter-bar. This projection 37 extends spirally across the inner face ofthe block so as to conform to the spiral shape of. the groove 38 withinwhich it works.v The block 36 is held yieldingly in positionaby'means ofsprings 39, which are preferably of the. fiat plate type, bearing uponthe block at their central portions and having tensioning bolts 40passing through their ends and screwing into the housing of the.stationary cross-head 5.

The feed-wheel 22 is rotated to turn the screw 21, and thus feed it intoand out of the shank 19, by means of a cam-bar 41 (see Fig. l), whichbar is adjustably secured to the movable cross-head 17, and has a curvedcam portion 42 on its lower end. Secured to the stationarycross-head 5at its upper edge is a plate 43, behind which there is guided by saidplate a feed-bar 44, said bar having a single tooth 45 that is adaptedto engage with ratchet teeth 46 on the outer curved surface of thefeed-wheel. 22. The feed-bar 44 is held in position by the plate 43 andby stop plates 47 which are secured to the plate 43 and project over thefeedbar. The feed-bar is reciprocated in one direction by the engagementtherewith of the curved extension 42 of the cam-bar 41 when it issubstantially at the extreme upper end of its movement, and it isreciprocated in the opposite direction by a spring 48, that is attachedto a pin 49 on the feedbar, said spring being also connected to thestationary cross-bar. The engagement of the pin 49 with the plate 47limits the movement of the feed-bar in a backward direction, while theengagement of a similar pin 50 with the other plate 47 limits themovement of the feed-bar in the other or feeding direction, the lengthof stroke given the said feed-bar being just suiiicient to turn thefeed-wheel the distance of one tooth. To prevent backward rotation ofthe feedwheel, its upper surface is toothed or notched at 51, and withthese teeth or notches engages a spring-pressed plunger-pawl 52, whichis inserted into a socket drilled into the lower end of the shank 19.The lower end of the plunger-pawl is flattened, as shown in Fig. 8, soas to effectually engage the teeth on the feed-wheel, and theplunger-pawl is limited in its travel by a pin 53, which projectsthrough and engages wlth the ends of a slotted opening 54 in the side ofthe shank 19 near its lower end. The plunger-pawl is forced outwardlyinto engagement with the teeth on the feed-wheel by means of a spring55, which is placed in the bottom of the socket behind the plunger pawl.

After the feed-wheel has been turned by the feed-bar 44, and thecutter-bar has started on its operating stroke, it is necessary toprevent the rotation of the feed-wheel with respect to the shank 19; andfor this purpose I pivot in a slot in the lower end of the shank 19 adetent pawl 56, said pawl having a V-shaped blade 57 projecting belowthe end of the shank and over the side of the feed-wheel in position toengage with the teeth 46 on said wheel. In Fig. 6 I have shown afragment of the housing of the stationary cross-head 5, from which itwill appear that the upper part of the bore through the housing, inwhich the cutterbar operates, is rounded or cammed at 57 The detent pawl56 is moved into engagement with the teeth on the feed-wheel by the saidcammed portion 57*, and is held in such engagement by the housing duringthe entire movement of the cutter-bar, except when it is substantiallyin its upper position, at which time the pawl 56 has passed so far outof the bore in the housing as to be thrown out of engagement with thefeedwheel by a spring 58. This spring is secured to the upper end of thepawl 56 be yond its pivot point, and lies in the bottom of the slot madein the shank 19 for said pawl;

Vith the construction above set forth, it will be understood that,during the upward stroke of the cutter-bar 23, the pawl 56 will be heldin engagement with the teeth of the feedwheel until the cutter-barreaches substantially the upper end of its travel, when the pawl 56 willbe thrown out of engagement with the feed-wheel so that the latter maybe turned. During said upward stroke of the cutter-bar, the feed-bar 44has been in the position shown in Fig. 11, with the pin 49 restingagainst the stop-plate 47, being held in that position by the spring 48.As the feed-wheel 22 is lifted, the tooth 45 on the feed-bar will enterthe space between two adjacent teeth 46, and, immediately thereafter,the pawl 56 will release said wheel so that it may be turned by the end42 of the cam-bar, which engages the rounded end of the feed-bar 44 andforces the latter to the left, as seen in Fig. 1, thereby turning thefeed-wheel the distance of one tooth, and screwing out the feed-screwfrom its shank a proportional distance. As the feed-wheel 22 is thusturned, the springpressed plunger 52 rides over a tooth 51, and drops inbehind the next adjacent tooth so as to prevent the return movement ofthe feed-wheel and the feed-bar 44. As the feed-wheel is forceddownwardly again with the cutter-bar, the pawl 56 is cammed intoengagement with the teeth 46 on the feedwheel, which thereby locks thefeed-wheel against rotation with respect to the shank 19. This downwardmovement of the feedwheel carries the latter away from the tooth 45 onthe feed-bar, which then snaps back to its normal position, with its pin49 against the stop-plate 47, ready for the next feeding operation. Theshank 19 is'of sub stantially the same diameter as the wheel 22 and thecutter-bar, and for that reason a groove 59 is cut in the shank toaccommodate the tooth 45 on the feed-bar as the shank travelsdownwardly. As appears from Fig. 6, the lower end of said groove 59 iswidened, for the reason that at the be ginning of the downward movementof the shank the tooth 49 is in its feeding position, and the length ofsuch widened portion is sufficient to permit the tooth to return tonormal position before it reaches the narrow part of the groove.

As the feed-screw 21 is screwed out of the shank 19, and the latter ismoved downwardly, the cones 29, 30 and 31 will be forced downwardly inthe cutter-bar, thereby forcing outwardly the cutter-bits 26. During thecutting stroke, the cutter-bar, the feed-wheel and the shank 19 abutclosely together, so that the strain due to the cutting action issustained by the parts-above named. During said cutting stroke, if thefeed-screw has been fed out of the shank, the cones 29, 30 and 31 willmove downwardly in the cutter-bar, so that the upper cone 29 will be outof contact with the internal shoulder 60 of the cutter-bar. During thereturn stroke of the cutter-bar, the

shank and feed-screw are first lifted, and

the cutter-bar remains stationary until the cone 29 contacts with theshoulder 60, after which the cutter-bar is lifted with the shank. Thereis thus established between the shoulder 60 and the upper cone as thefeed-screw is turned, a gradually increasing lost motion, the extent ofwhich governs the extent of outward motion of the cutter-bits.

To prevent the cutter-bits from being fed out too far, andto hold theparts in proper position, I attach to the lower end of the cutter-bar aring 61, said ring being secured by means of screws 62, which enter thelower end of the cutter-bar. This ring has an opening at its centerwhich is slightly less than the diameter of the cone 31, so that whensaid cone is fed downwardly in contact with the ring, the cutter bits 26will not be fed outwardly any farther. The extent to which thecutter-bits may be fed outwardly may be regulated by a screw 63 in thering 61, the upper end of said screw extending into the path of movementof cone 31. By adjusting this screw inwardly and outwardly, the cone 31will contact earlier or later therewith, and thus the depth of theflutes to be cut will be regulated.

Vhen the desired depth of the flute is obtained, the machine may beautomatically stopped by having the lower end of the feed-screw 21engage with an adjustable screw 64 on a trip-lever 65 which is pivotedat 66 to a bracket 67 that is carried by the lower cross-head 6. Theouter end of the lever 65 is connected to a vertically extending link 68that is pivoted to the inner end of a catch lever 69. This catch leveris pivoted at 70 to the housing 1, and it has its outer end providedwith a hook 71 which engages with a belt-shifting lever 7 2. Thebelt-shifting lever has its rear end forked to engage with the oppositesides of the belt 11, and has its other end extending forwardly at 73into a position such as will be convenient for the operator to graspwith his hand when he desires to start the machine. From this it'will beunderstood that, when the operator starts the machine, he pushesoutwardly on the end 73 of the shift ing-lever until the belt 11 iscarried from the loose-pulley 9 to the driving-pulley 10, when the lever72 will be caught by the catch lever 69 and held with the belt indriving position. When the flutes are cut to the desired depth, thecatch lever 69 will be automatically rocked to release the belt shiftinglever 72, whereupon a spring 74, which is connected to the said leverand to the frame of the machine, automatically throws the belt off ofthe drive-pulley and on to the loose'pulley 9.

The cutter-bar 23 is of substantially the be formed which will bindagainst the cutter-bar, thereby producing friction and wear. For thisreason, shallow s iral flutes 7 5 are cut on the cylindrical surface ofthe cutter-head in positions corresponding with the cutting faces on theprojections 34, so that the bur formed by cutting the flutes will followin the said shallow flutes and thereby avoid such wear and friction.

The housing into which the flutes are to be cut is of the form of ahollow tube; and, for supporting said housing in its proper position, Iconnect with the lower stationary cross-head 6, a collar 75, having aninternal shoulder 76 against which the lower end of the said housing isto rest. Also, screw threaded upon the lower end of the stationarycross-head 5, is a somewhat similar collar 7 7 having an internalshoulder 7 8 which rests upon the upper end of the said housing. Byplacing the housing in position between these two collars, and byscrewing downwardly on the collar 7 7 said housing may be securelyclamped into position and held during the cutting operation.

WVhile I have necessarily shown and described one embodiment of myinvention, I appreciate the fact that the principle of the invention maybe embodied in machines diflering in details from those shown anddescribed, and I therefore desire it to be un derstood that thefollowing claims are not limited to such details any further than isrendered necessary by the terms expressly employed therein.

Having thus described my invention, I claim:

1. In a machine for cutting internal grooves, a main frame, areciprocating crosshead mounted in said frame, a feed-screw, afeed-wheel connected with said feed-screw, a cutter-bar connected withthe cross-head and reciprocating therewith, a cutter-bit carried by thecutter-bar, connections between the cutter-bit and the feed-screw, suchthat, when the feed-screw is turned, the cutter-bit will be forcedoutwardly, means for turning the feed-wheel and the feed-screw at adefinite time in the stroke of the cutter-bar and means for locking thefeed-wheel and the feed-screw against rotation except at the time whenthe same is to be turned.

2. In a machine for cutting spiral, internal flutes, a main frame, areciprocating cross-head mounted in said frame, a feedscrew connectedwith the said cross-head, a feed-wheel feathered to said feed-screw, acutter-bar connected with. the cross-head and reciprocating therewith, acutter-bit carried by the cutter-bar, connections between the cutter-bitand the feed-screw, such that when the feed-screw is turned in thecutterbar, the cutter-bit will be forced outwardly, means for turningthe feed-wheel and the feed-screw at a definite time in the stroke ofthe cutter-bar, means supported from the cross-head for locking thefeed-wheel and the feed-screw against rotation except at the time whenthe same is to be turned, and mechanism for turning the cutter barduring its reciprocations.

3. In a machine for cutting internal flutes, a main frame, a cross-headmounted to reciprocate in said main frame, a shank depending from thecentral part of said cross-head, said shank having a threaded socket inits lower end, a feed-screw threaded in said socket, said screw having afeather-way formed therein, a feed-wheel feathered to said feed-screw, acutter-bar supported by and surrounding the said feed-screw, acutter-bit mounted in said cutter-bar, connections between thecutter-bit and the feedscrew whereby, when the feed-screw is screwed outof the shank, the cutter-bit is fed outwardly from the cutter-bar, meansfor guiding the cutter-bar in its reciprocation, means carried by saidguiding means for turning the feed-wheel and means carried by the shankand engaging with the guiding means for locking the feed-wheel and thefeed-screw against rotation during the cutting operation.

4. In a machine for cutting internal grooves, a main frame, a cross-headmounted to reciprocate in said frame, a shank depending from the centralportion of said cross-head, said shank having a threaded socket in itslower end, a feed-screw threaded into said socket, said feed-screwhaving a feather-way therein, a feed-wheel feathered on the feed-screwbelow the shank, a cutterbar carried by the feed-screw, said cutterbarhaving an opening therethrough for the feed-screw, a cutter-bit mountedin the lower end of said cutter-bar, connections be tween thecutter-bit, and the feed-screw, such that, when the feed-screw isturned, the cutter-bit will be fed outwardly from the cutter-bar, astationary guide for the cutterbar, a feed-bar mounted upon thestationary guide and having a tooth for engaging the feed-wheel, meanscarried by the cross-head for moving the feed-bar to turn the feedwheeland means carried by the shank for locking the feed-wheel againstrotation during the descent of the cutter-bar.

5. In a machine for cutting spiral internal grooves, a main frame, across-head mounted to reciprocate in said frame, a shank depending fromthe central portion of said cross-head, said shank having a threadedsocket in its lower end, a feed-screw threaded into said socket, saidfeed-screw having a feather-way therein, a feed-wheel feathered on thefeed-screw below the shank, a cutter-bar carried by the feed-screw, saidcutter-bar having an opening therethrough for the feed-screw, acutter-bit mounted in the lower end of said cutter-bar, connectionsbetween the cutter-bit and the feed-screw, such that, when the feedscrewis turned, the cutter-bit will be fed outwardly from the cutter-bar, astationary guide for the cutterbar, a feed-bar mounted upon thestationary guide and having a tooth for engaging the feed-wheel, meanscarried by the cross-head for moving the feed-bar to turn the feedwheel,means carried by the shank for looking the feed-wheel against rotationduring the descent of the cutter-bar, and means for rotating thecutter-bar during the cutting operation.

6. In a machine for cutting internal grooves, a main frame, areciprocating crosshead mounted in said frame, mechanism forreciprocating said cross-head, a feed-screw supported from saidcross-head, means for turning said feed-screw, a cutter-bar supportedfrom the cross-head, a cutter-bit carried by the cutter-bar, connectionsbetween the cutter-bit and the feed-screw, such that when the latter isturned, the cutter-bit will be fed outwardly from the cutter-bar, atriplever adapted to be engaged by the feedscrew after the same has beenturned to a predetermined extent and connections between the trip-leverand the mechanism for reciprocating the cross-head, such that, when saidtrip-lever is operated, said mechanism will be automatically stopped.

7. In a machine for cutting internal grooves, a main frame, a shaftjournaled in said frame, a loose and a fast pulley carried by saidshaft, a cross-head mounted in the main frame, connections between saidshaft and said cross-head for reciprocating the latter as the shaft isrotated, a belt for driving the pulleys, a cutter-bar supported fromsaid cross-head, a feedscrew connected with the cutter-bar, a cutter-bitcarried by the cutter-bar, connections between the cutterbit and thefeed-screw such that, when the latter is turned the cutterbit will befed outwardly from the cutter-bar, and means for automatically shiftingthe belt from the fast to the loose-pulley when the cutter-bit has beenfed outwardly to a predetermined distance.

8. In a machine for cutting internal flutes, the combination of a mainframe, a crosshead mounted to reciprocate in said frame, means forreciprocating said cross-head, a shank depending centrally from saidcrosshead, said shank having a central threaded socket in its lower end,a feed-screw threaded into said socket, said feed-screw having afeather-way therein, a feed-wheel feathered to said feed-screw, atubular cutter-head below said feed-wheel and through which the saidfeed-screw extends, cone members carried by the lower end of saidfeed-screw within the cutter-bar, said cutting-bar having a plurality ofradial slots opposite said cones, a cutter-bit mounted in each of saidradial slots, angular parallel arms projecting from the rear of each ofsaid cutter-bits and between the conical faces of said cone members,means for turning the feed-wheel as the cutter-bar reciprocates, wherebythe feed-wheel is screwed out of the shank and the cones are caused tofeed the cutter-bits, carrying the same outwardly and maintaining themparallel with their former positions, and means for locking thefeed-wheel and feed-screw against rotation during the cutting strokeofthe cutter-bar.

9. In a machine for cutting spiral, internal flutes, the combination ofa main frame, a cross-head mounted to reciprocate in said frame, meansfor reciprocating said cross head, a shank depending centrally from saidcross-head, said shank having a central threaded socket in its lowerend, a feedscrew threaded into said socket, said feedscrew having afeather-way therein, a feedwheel feathered to said feed-screw, a tubularcutter-head below said feed-wheel and through which the said feed-screwextends, cone members carried by the lower end of said feed-screw withinthe cutter-bar, said cutter-bar having a plurality of radial slotsopposite said cones, a cutter-bit mounted in each of said radialslots,angular parallel arms projecting from the rear of each of saidoutter-bits and between the conical faces of said cone members, meansfor turning the feedwheel as the cutter-bar reciprocates, whereby thefeed-wheel is screwed out of the shank and the cones are caused to feedthe cutterbits, carrying the same outwardly and maintaining themparallel, with their former positions, means for locking the feed-wheeland feed-screw against rotation during the cutting stroke of thecutter-bar, and means for turning the cutter-bar as it reciprocates.

10. In a machine for cutting internal grooves, a main frame, across-head mounted to reciprocate in said frame, means for reciprocating the cross-head, a shank depending centrally from saidcross-head, said shank having a central threaded socket in its lowerend, a feed-screw threaded into said socket and having a feather-waytherein, a

feed-wheel feathered to said feed-screw, a cutter-bar, a cutter-bitcarried by the cutterbar, connections between the cutter-bit and thefeed-screw, such that, when the latter is turned, the cutter-bit will befed outwardly from the cutter-bar, a guide housing for the cutter-bar, afeed-bar mounted to reciprocate on said guide housing, said feed-barhaving a tooth that is adapted to engage with teeth on thecircumferential surface of the feedwheel, a plunger pawl carried by theshank and adapted to engage teeth on the upper surface of the feed-wheelto prevent reverse rotation of the latter, means carried by thecross-head and adapted to engage the feedbar to turn the feed-wheel anda detent pawl secured to the shank and engaging with the guide housing,whereby the pawl is ,moved into locking engagement with the teeth on thecircumferential surface of the feedwheel for locking the latter duringthe cutting stroke of the cutterbar.

11. In a machine for cutting spiral, internal grooves, a main frame, across-head mounted to reciprocate in said frame, means for reciprocatingthe cross-head, a shank depending centrally from said cross-head, saidshank having a central threaded socket in its lower end, a feed-screwthreaded into said socket and having a feather-way, a feedwheelfeathered to said feed-screw, a cutterbar, a plurality of cutter-bitscarried by the cutter-bar, connections between the cutterbits and thefeed-screw, such that, when the latter is turned, the cutter-bits willbe fed outwardly from the cutter-bar, a guide housing for thecutter-bar, a feed-bar mounted to reciprocate on said guide housing,said feedbar having a tooth that is adapted to engage with teeth on thecircumferential surface of the feed-wheel, a plunger-pawl carried by theshank and adapted to engage teeth on the upper surface of the feed-wheelto prevent reverse rotation of the latter, means carried by thecross-head and adapted to engage the feed-bar to turn the feed-wheel, adetent pawl secured to the shank and engaging with the guide housing,whereby the pawl is moved into locking engagement with the teeth on thecircumferential surface of the feed-wheel for locking the latter duringthe cutting stroke of the cutter-bar, and means for rotating thecutter-bar as it reciprocates. I

12. In a machine for cutting spiral flutes, a main frame, a cutter-barmounted to reciprocate in said frame, said cutter-bar having a spiralexternal flute, a cutter-bit carried by said cutter-bar, means forfeeding said cutter-bit outwardly from the cutter-bar, a guide housingfor the cutter-bar, a pressed block mounted in the guide housing, saidblock having a tongue extending into the spiral flute on the cutter-barand a spring for holding said block in position.

13. In a machine for cutting spiral, internal flutes, a main frame, acutter-bar mounted to reciprocate in said frame, said cutterbar having aspiral external flute, a plurality of cutter-bits carried by saidcutter-bar, means for feeding said cutter-bits outwardly from thecutter-bar, said means maintaining the cutter-bits parallel to theirformer positions in the cutter-bar, a guide housing for the cutter-bar,a pressed block mounted in the guide housing, said block having a tongue

